Cooker/rethermalizer

ABSTRACT

A food cooker/rethermalizer especially suited for cooking or for reheating of prepared, packaged meat and sauce entree items, and optionally for cooking vegetables. The apparatus includes a multiple of food item receiving locations defined by a locator rack, and fluid ejecting tubes beneath the locations to eject fluid such as air therefrom, which rise over the package surfaces for bath mixing and efficient and uniform heat transfer. The tubes include a pair of upwardly sloped conduits oriented in opposite directions and which eject fluid at the upper ends of the tubes, on opposite sides of the bath, to cause circulation of the heated liquid bath. The bath is heated by resistance coils embedded in rubber bonded to the outside of the vessel. The bath level is controlled by a dual temperature sensor device, one sensor above the other, to detect a predetermined temperature differential and activate a water supply valve to inject only small quantities of water. The heating chamber is separated from the electronics control chamber by a space which has a thermally generated convection cooling action. The defined locations of the locator rack have a geometric arrangement matching the geometric arrangement of controls on a control panel. 
     If the unit is used to cook pasta, the rising fluid not only assists with bath mixing and cooking action, but also keeps the pasta from sticking together, while the sloped ejection tubes of the basket function to eject starch floating on the bath out of the vessel.

BACKGROUND OF THE INVENTION

This invention relates to a heating apparatus, particularly a foodcooker and/or rethermalizing apparatus.

Food Service food preparation in recent years has involved conveniencefoods or convenience packaged foods for easier preparation or cooking.Typically, this involves one of two known techniques using flexible filmpackages, namely: 1) so-called "cook-chill," and 2) so called "sousvide". These two are known to be excellent systems for supplying highquality, nutritious, previously prepared food, ready for reheating toprovide meals. The technique known as cook-chill involves soups, sauces,and other products of pumpable consistency. The product is cooked at afacility separate from restaurants, or the like, where it is pumped intostrong plastic casings, closed by clipping or heat sealing, then chilledand kept under refrigeration, optionally frozen. Non-traditionalcook-chill products such as pasta, rice, and vegetables are alsobecoming popular.

In contrast to this cook-chill technique described above, the sous videtechnique involves packing of raw or partially cooked products intoplastic pouches under vacuum, then cooking, and finally chilling eitherto frozen or nonfrozen condition.

Sous Vide technique is typically used for a variety of meat or fishentrees. These refrigerated, vacuum packaged foods are then reheated inselected groupings at the restaurant or other location, in response tocustomer orders. Experience has demonstrated that such carefullyprepared food items can be of excellent quality, satisfactory to eventhe most discerning palates.

When properly treated, these previously prepared foods enable serving ofhigh quality food without having the expense and complications of atalented chef on staff at restaurants and/or institutions, or withoutrequiting extended cooking time if done at home. Preparation can berapid, relatively inexpensive, and far less complex than in a typicaloperation.

The excellent quality of this food preparation technique is too oftenlost in the reheating process. The difficulty has been found to occurlargely as a result of inaccurate temperature control and/or variableheat transfer rates during the reheating process. In fact, properheating has been found to be critical to high quality results. Heatingin boiling water tends to destroy food quality. Placing the packages inhot water below the boiling temperature for a selected time may or maynot result in satisfactory food. The resulting temperature of the foodproduct may be too high or too low. What can occur is that a meatserving, for example, is overheated and tough while another portion isnot fully heated. Efforts have been made to circulate the reheatingwater medium by using circulation pumps as in Vilgrain et al U.S. Pat.No. 5,097,759; but this is not considered an adequate solution forconsistent food quality. The bath water does not flow evenly over allsurfaces, but rather takes the path of least resistance. Further, thebath water tends to stratify into thermal layers of differenttemperatures. It has been determined that the bath tends to heatunevenly. Even if the heat is spread over the surface of the vessel, itwill separate into laterally adjacent zones, each having a width ofabout six inches or so. These all tend to prevent controlled temperaturecooking or reheating in a hot water bath. Controlled proper heating orrethermalizing of the servings is further complicated by the fact thatseveral different packages of different food are typically put into thebath during a particular time period, and these are inserted atdifferent times in response to successive customer orders received.Hence, even though complexities due to meals not being totally preparedby the restaurant kitchen are bypassed, still the cooking orrethermalization of many individual meals and various components ofthose meals can become chaotic and difficult to properly perform.

Portions of food products in flexible film packs have only, until now,been cooked successfully in Sous Vide or Cook Chill preparationfacilities wherein the equipment is large, special purposed, andmonitored by computers including special temperature probes insertedinto food portions in the processing chamber.

In general, standard restaurant or home reheating/cooking equipment isunsuited to cooking and poor at reheating food products in flexible filmpackages. The standard equipment is characterized by poor control ofoperating temperatures. Cooking is accomplished using a cooking fluid ofwater, air or oil. Temperature differences in an oven typically amountto 20° F. and can significantly affect quality unless a chef is there tointerrupt or modify the cooking process appropriately. Even so, airtransfers heat so much slower than water and has very little storedenergy, so the oven is somewhat forgiving when cooking unpackaged food,but is unsuited to cooking or reheating flexible film packaged food.

Fryers use oil or shortening as the temperature transfer media and havevery sophisticated control systems to hold temperatures within a fewdegrees. Even so, they require either a chef of great experience tomonitor the cooking or the even more sophisticated frying computers asin Polster U.S. Pat. No. 4,362,094 to achieve consistent qualitycooking. The operating temperatures of fryers is unsuited to cooking orreheating flexible film packaged food.

Pots or pans of hot or boiling water are good for cooking eggs andvegetables. They are unsuited for cooking or reheating flexible filmpackaged food.

Typical Bain Marie's have a heater in the bottom of a large bath ofwater. Often a temperature control is used to control the temperature ofthe bath. If a load of food product is introduced into one portion ofthe bath, the remaining portion of the bath will either go to a muchhigher temperature (often boiling) or the area where the food has beenintroduced will drop in temperature depending on where the temperaturecontrol sensor is located. In either case all or some of the food willbe heated at the wrong temperature and in one case the remaining area ofthe bath will be at the wrong temperature for the introduction of morefood products.

In restaurant kitchens, another known severe problem that significantlyaffects cooking is water level control for heating bath vessels. Waterlevel is typically established manually by adding cold or hot water tothe heated vessel to replace water lost by evaporation and by watertransfer with the packaged food items removed. Adding this water to aheated vessel, usually in a significant quantity by the time the bathdecline is noticed, typically causes a significant temperature change,usually a decline, in the bath. Even if heated water is added, itstemperature will most likely be many degrees different from the bathtemperature. This alters the cooking/reheating process and thus altersthe time required to cook or reheat the food items in the bath.

When cooking pasta in boiling water, the action of the boiling keeps thepasta from sticking together. Most modern pasta cooking systems have aperforated basket that drops into the boiling water and contains thepasta to be cooked. The boiling action does not occur within theperforated basket and the operator is obligated to stir the pasta whilecooking to keep it from sticking together. Therefore modem pasta cookingsystems actually cook pasta in hot water which does not have enoughcirculating action to properly cook it.

Another more subtle obstacle to proper cooking/reheating in a water bathhas been discovered to be the standard proportioning temperature controltechnique which compensates for lag time and the thermodynamics of thewater bath itself. The problem is that such techniques are notresponsive to highly variable loads. Therefore in order to avoid thedisasterous overshoot of temperature of an on-off control system, therecovery time of a proportioning temperature controlled water bathvaries dramatically with load which changes the time to cooksignificantly. This problem is unobvious as the water bath seems toperform by properly coming to temperature without overshoot and thevariations in cooking are mysterious.

When dealing with hot water baths, even 5° F. significantly changes thetexture of many foods to be cooked. Temperatures should be held withinabout 2° F. of the optimum temperature. Circulation of the fluid helpsto prevent temperature layer stratification, but circulation alonewithout exact bath temperature control is not enough. Further, thepresence of circulation does not necessarily assure even flow over allsurfaces of the food items. This flow over all surfaces of the fooditems is important for proper cooking or reheating. The mere presence ofthe food items disturbs the circulation pattern of any cooking vessel,with the fluid taking the path of least resistance and not the pathsbetween all the food items, especially if the paths are narrow. Fluiddynamics in the cooking vessel present problems.

It has been found by the inventor herein to be important, for propercooking or rethermalization, that the temperature be retained in aclosely controlled range, for there to be totally efficient heatexchange with the surfaces of each of the several packages or items offood being cooked or reheated, for each item to be heated in accordancewith the type of food in the package, i.e., for each type of entree,sauce, pasta, and vegetable etc. to be heated for an exact predeterminedamount of time and at a temperature which is optimum for that entree orsauce. Achieving these results with present cooking or rethermalizationequipment does not dependably occur. As noted, if too high a temperatureis used, the food becomes overcooked and the texture is adverselyaffected. If too low a temperature is used, the food is not properlycooked. If the temperature changes, the food chemistry changes.

It has also been found that vegetables can be cooked in the water bath,using the above mentioned principles, loose or in a perforated flexiblefilm package, or reheated after initial cooking and vacuum packaging.

Another discovery was that the bubbles uses to vertically pertebate thewater bath between food packages kept pasta from sticking together eventhough the bath was not boiling. The bubbles also facilitated theremoval of the starch that is cooked out of the raw pasta. The starchand a small amount of water was then found to be removed from the bathby the bubble driven circulation system. The water level control systemmade up the water lost removing the starch.

SUMMARY OF THE INVENTION

The inventor herein has developed a unique apparatus for cooking orrethermalizing food. It achieves fluid flow action over the surfaces ofall of the food packages in a cooking or rethermalizer vessel, forexcellent heat exchange with the packages. The invention provides aunique cooking/rethermalizing apparatus and system which effects uniformcooking, or uniform reheating of individual portions of previouslyprepared and packaged food. The apparatus effects uniform heating offood items, even when placed anywhere in the heating bath at differenttimes. At the time the food item is placed in the bath, retained by foodlocating and support means, the particular type of food item and itslocation in the bath are entered in a controller which has a controlpanel that visually corresponds to the geometry of the defined locationsof the locator rack in the thermalizing bath. Each food serving isuniformly and properly heated. Each package is retained in position,separated from other packages, in a locator rack retainer which employsa unique fluid generator system, preferably for generating bubbles, tosimultaneously, 1) hold the packages in proper orientation in locations,2) separate the packages from other packages in these locations, 3)cause flow over all of the package surfaces in all of the locations foruniform efficient heat exchange, and 4) cause bath liquid circulationwithin the vessel throughout the several defined locations. The retaineris an open top, open mesh locator rack which defines these locations forthe packaged individual food items, and has tubes to generate flowingfluid, preferably air bubbles, between all the locations for causingfluid scrubbing over all of the package surfaces as the bubbles rise tothe surface. This flow action causes excellent heat exchange at thepackage surfaces, as well as elimination of temperature stratificationfor accurate and efficient heat transfer to the food. The tubespreferably include diagonally, upwardly, outwardly oriented, i.e,sloped, tubes or ramps extending in opposite directions on oppositesides of the vessel, for discharge of a fluid, preferably a gas such asair, in opposite directions, causing the bath to circulate continuously.

Another object of this invention is to provide a cooking/rethermalizingvessel bath level control using specially arranged and cooperativetemperature sensors. Controlled automatic injection of small quantitiesof replacement water occurs frequently, as necessary. The only openingsneeded in the vessel itself are the open top and a bottom drain. Theinvention herein uses a unique, vertically displaced, temperaturesensing and responsive water level control system. It senses temperaturedifferential between different vertical locations of the vessel, tocause added water to be included in small regular quantities as needed.The sensors are vertically spaced on the outside of the vessel, todetect the temperature differential between a portion of the vesselconstantly containing the heated bath and a portion which may or may notcontain the heated bath, to control replacement water input in responseto this temperature differential sensing.

The vessel is heated in laterally adjacent zones for control. Further, atemperature sensor is located on the vessel for each zone, near theheater to cooperate with sensors near the vessel bottom, to compensatefor lag time, i.e., thermal momentum, and thereby prevent seriousovershoot of the rising temperature above the optimum temperaturedesired. This arrangement minimizes recovery time.

Another object of this invention is to provide cooking/rethermalizingbath apparatus enabling direct easy control and monitoring of individualservings of food placed in the bath, even though the items are ofdifferent foods, even though they are placed in the bath at differenttimes, and in different parts of the bath. The food retaining means inthe bath has its plurality of locations arranged in a geometric patternwhich visibly anti pictorially corresponds to a similar control panelgeometric pattern, with a timer control and indicators for therespective locations.

The housing of the rethermalizer has its control system mounted in anelectronic control chamber separated from the cooking chamber by a pairof spaced vertical walls, the space between the walls being verticallyelongated and having openings at the bottom and at the top thereof tocause thermally generated air flow entering at the bottom and departingat the top, thereby effecting a cooling action/thermal isolation overthe wall of the electronic control chamber. This creates a chimney typeflow, convection cooling action that isolates the control chamber fromthe cooking vessel.

Another object of the invention is to provide a cooker/rethermalizerwhich can serve as a special cooker for pasta. The present inventionenables pasta to be cooked in a container inside the main bath vessel,with fluid flow action up through the pasta inside the container foruniformly cooking, preventing the pasta from sticking together and forelevating starch to the surface.

Furthermore, the novel apparatus automatically removes the cooked starchfloating on the surface of the bath, achieving this discharge by thesame fluid flow tube structure which circulates the bath. The floatingstarch is upwardly, outwardly ejected from the vessel by fluid ejectedfrom the ends of diagonally, upwardly, outwardly oriented tubes. Asnoted, these tubes include a pair on opposite sides of the cookingvessel, to also cause circulation of the liquid bath. Another object ofthis invention is to provide a cooking/rethermalizing system that allowsseparate temperature control of laterally adjacent bath zones in thevessel, to match the zone heat input to the load of that zone, and in afashion minimizing temperature overshoot in another zone.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of the cooker/rethermalizer of thisinvention;

FIG. 2 is a top plan view of the apparatus in FIG. 1;

FIG. 3 is a front end view of the apparatus;

FIG. 4 is a rear end view of the apparatus;

FIG. 5 is a side elevational view, partially in cross section, showingthe heater vessel, the bottom drain therefrom, and the double wallbetween the heater chamber and the control electronics chamber, with theretainer rack for supporting food packages removed therefrom;

FIG. 6 is a top plan view of the apparatus with the retainer rack forsupporting food packages removed therefrom;

FIG. 7 is a side elevational view of the food item supporting retainerrack, including fluid tubes;

FIG. 8 is a top plan view of the basket in FIG. 7;

FIG. 9 is an end elevational view of the retainer rack in FIGS. 7 and 8;

FIGS. 10A and 10B are a circuit diagram of the control system;

FIG. 11 is a perspective view of the control module with its controlpanel;

FIG. 12 is a front elevational view of the cooker/rethermalizer and itscontrol system; and

FIG. 13 is an enlarged, fragmentary, cross sectional view of a portionof the bottom of the heating vessel.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now specifically to the drawings, the complete combination 10(FIG. 12) of the cooker/rethermalizer assembly 12 and the control moduleassembly 14 are there illustrated.

The assembly 12 includes a housing 18 made up of a plurality of fourwalls, i.e., two side walls 20a, a front end wall 20b, and a rear endwall 20c. Housing 18 rests upon a plurality of feet 28, and is dividedinto two chambers, namely a heating chamber 22 (FIG. 5) and anelectronic control chamber 24. These chambers are separated from eachother by a vertically elongated, transverse space 26 having the rearheating chamber wall 22a on one side and the front electronic controlchamber wall 24a on the other side. Electronic control chamber 24includes three outside walls and inside wall 24a. Space 26 extendstransversely across the entire unit, having one or more openings 26a atthe bottom thereof for entry of cooling air and one or more top openings26b, preferably into heating chamber 22, for flow of air out of space26. Thermal energy from chamber 22 creates a chimney-type convectionflow effect relative to space 26, the thermally generated air movementthus constantly moving up through space 26. This cools wall 24a and thusthermally isolates control chamber 24 from heating chamber 22, tomaintain the electronic control components relatively cool, i.e., at asignificantly lower temperature compared to that of heater chamber 22.In the front wall 20b is a pair of outlet vents 20d to allow heated airfrom chamber 22 to escape. The side walls of the control chamber 24include a plurality of vents 20e, and rear wall 26c includes a furtherplurality of vents 30f, enabling the electronic control chamber 24 to beflushed constantly with cool ambient air.

Within heater chamber 22 is a heater vessel 30, preferably of stainlesssteel, and having four side walls 32, i.e., a front wall, a rear walland two lateral walls, all integrally joined, as well as a bottom wall34 integrally joined with the four side walls to form an open topvessel. Other than the open top, the only opening into the vessel is adrain outlet conduit 36 in vessel bottom 34. This drain may becontrolled by a valve actuator 38 which protrudes from the front of therethermalizer housing.

Within vessel 30 is placed a special food item retaining locator rack 40depicted in FIGS. 2, 7, 8 and 9. This locator rack comprises an openmesh type of structure formed of elongated elements, largely wire-typeor tubular-type elements, preferably of stainless steel metal, forming abottom and four upstanding walls. Several portions of these elements arespecially adapted to conduct fluid, preferably gas and normally air, butpotentially fluid such as water, therethrough, in a manner explainedhereinafter for purposes explained hereinafter. It is not necessary thatall components of the locator rack be hollow or that they all be capableof conducting fluid, but it is significant that they be constructed sothat fluid discharge will emanate therefrom into the heated fluid bathin a manner causing bath mixing action and flow along the surfaces ofall of the packages of food placed in special defined locations definedby the locator rack. In the preferred embodiment depicted, there is anelongated wire element 42 (FIG. 7) which extends the length of therectangular shaped locator rack depicted, this being shown to runthrough the center of the rack dividing it into two visual majorlocations. Two roughly triangular elongated wire elements 42a define thesides of the locator rack and provide a place for the U-shaped ramps tobe attatched. These three elongated wire elements are showninterconnected by a plurality of bottom transverse wire elements 44which are normal to elements 42, and here shown to be nine in number, tounderlie 18 locations in this embodiment. Two top wires 44a further(visually) divide the locator rack into a total of six primary locationseach with three locations totalling the 18 locations, formed by thelocator rack. These locations have vertical walls formed by upstandinginverted U-shaped wires 46 attatched to the bottom transverse wireelements 44. The wire elements 44a and 42 thereby divide the basketvisually into the primary-locations. Two inverted, U-shaped side handles48 for lifting the locator rack out of the heater vessel are attatchedto wires 42a and 44a.

The locator rack also includes special fluid conducting and releasingtubes. More specifically, one longitudinal pair of tubes 50 extendsbeneath the 18 locations, each tube extending beneath nine locations onits respective side of the rethermalizer vessel.

Each of these tubes or tubular elements 50 has a plurality of outletorifices, preferably on the underside thereof, along the length thereof,to allow a pressurized fluid such as gas, typically air, to be ejectedfrom the tubes along the length thereof. Air bubbles thus will form,rising gravitationally to the surface of the aqueous bath contained invessel 30, moving up over the surfaces of packages of food positioned inthe locations defined by the locator rack, thereby mixing and disturbingthe bath water over the surfaces of the packages to promote uniformtemperature and efficient heat exchange with the food products beingheated. On opposite sides of the locator rack are diagonally arranged,upwardly outwardly sloped, inverted U-shaped ramps which areinverted-trough or tunnel-type conduits 60 (FIG. 7). Each of these hasan air inlet at one end, namely the lower end thereof, and an outlet atthe opposite upper end. These inverted trough-type conduits extendupwardly in the opposite direction relative to each other. Conduit 60ais shown to have an elongated air tube 62a extending along the undersideof the locator rack, almost the full length thereof, and then bendinglap in a U-turn to a gas outlet 64a (FIG. 7) into the inverted trough orU-shaped member 60a. Any pressurized fluid, e.g., air, passing throughtube 62a to outlet 64a will then form bubbles which flow up the slopedinverted trough 60a pushing the bath fluid ahead and both being ejectedat the upper end of trough-type conduit 60a in a diagonal directiontoward the rear end wall of the rethermalizer. On the opposite side ofthe vessel, a short hollow tube 62b extends to an outlet 64b beneath thelower end of inverted trough-type tube 60b for ejecting air or otherfluid up into and through this trough. The fluid then forms bubbleswhich flow up the sloped inverted trough 60b pushing the bath fluidahead and both being ejected at the upper end thereof which faces in theopposite direction, i.e., toward the front wall of the rethermalizer.The flow of the bubbles and bath fluid through the outlets of thetube-type members or ramps 60a and 60b causes circulation of the aqueousbath within the vessel. That is, the two operating together assureconstant recirculation of the aqueous bath around the, vessel andthrough the locations to optimize temperature uniformity by sweepingheated water away from the side and bottom of the vessel and to helpreduce the tendency of the water to stratify into thermal planes ofdifferent temperature. These hollow fluid tubes 50 and 62a and 62b areeach connected to a source of pressurized fluid such as air (not shown)by releasable connectors of conventional type, more specifically, e.g.,tubes 50 having quick connect couplings 70 (FIG. 2) and tubes 62a and62b having quick connect couplings 72a and 72b, respectively.

Bonded to the bottom and the lower side walls of vessel 30 (FIG. 5) is aheater 80. (FIG. 13). This heater is preferably formed of a pair oflayers of rubber-like material, preferably silicone rubber polymer, onelayer 82 being bonded to the outside surfaces of the bottom 34 and sidewalls 32 of vessel 30 (FIG. 13). Embedded between layer 82 and a secondpolymer layer 84 of rubber-like material such as silicone rubber polymerare electrical resistance coils 86. The embedded coil and rubber layersare therefore formed into an integral part of the heater vessel formingpart of the example circuitry in FIGS. 10A and 10B. This circuitry isone possible variation of the control system. Alternate solid statesystems could be used as will be apparent to those in the art. As notedin FIG. 10B, these resistance heaters are shown in three zones, heatzone A, heat zone B and heat zone C, sequentially along the length ofthe vessel (FIG. 5), each heat zone supplying heat for two side-by-sidecompartments, i.e., six locations, and each heater shown here to be ofabout 1667 watts. The reason for having the heaters in zones is thatuneven loading without zones, if sensed, would heat the entire bath inresponse to the sensed load causing the rest of the bath to overheat. Ifthe load was unsensed without zones, the loaded section would lower intemperature. Circulation does not instantaneously mix and even out wateror other fluid temperatures. Each zone, therefore, is separately heatedin response to the temperature sensing devices for that zone, mounted tothe outside surface of the vessel. More specifically, each heatingelement is responsive to the average of the temperature noted by a lowerthermal sensor 81' and the corresponding one of the upper thermalsensors 81 (FIG. 5) mounted to the vessel 30 at longitudinally spacedlocations adjacent the three zones respectively, and at a positionwithin the heater robber and at a specific distance from the nearestheater coil. The heater layer purposely does not cover the lower comersof the vessel, with two of the lower temperature sensors 81' beingmounted to the vessel wall at the comers (FIG. 5). As noted, the averagereading on upper sensor 81 and lower sensor 81' is used to control theheater for each zone. The location of the upper sensors 81 adjacent theheater enables these sensors to quickly detect rising temperature so asto compensate for lag time and therefore eliminate temperatureovershoot, i.e., potential overrun of the temperature in a zone. The useof the average between the lower and upper sensors minimizes the effectof any tendency of the bath in that zone to stratify in differenttemperature layers and it makes the control extremely sensitive to loadintroduction for quick response time.

In addition to the three pairs of temperature sensors 81 and 81'(FIG. 5,and see also FIG. 10A) for the heater units, there is also provided anovel bath level control, in the form of water level control,temperature sensors 83 and 83' (FIG. 5 and FIG. 10B), comprising afourth temperature sensor device in the circuit. Specifically, thisfourth sensor device comprises at least one pair of temperature sensors83 and 83' mounted to outer wall surfaces 32 of heater vessel 30,vertically spaced from each other, the lower one 83 establishing a setpoint temperature of the vessel wall always in engagement with bathwater, and the upper one 83' being located at the height desired for theaqueous bath level above the heater jacket and above sensors 81. Thetemperature differential between the two sensors 83 and 83' is operablyconnected with a water supply and control valve 85 (showndiagrammatically in FIG. 4). If the heated water level drops below thelevel of the upper sensor, that upper sensor will detect a significantlycooler vessel wall temperature than the lower sensor which is stilladjacent the heated bath water. At a predetermined temperaturedifferential between them, the sensors activate the water inlet valve85, allowing a small amount of added water, preferably water heated tothe same temperature as the bath, to be incorporated into the bath. Thisoccurs repeatedly on a short time interval basis as the water levelrepeatedly declines slightly due to evaporation and due to water loss byclinging thereof to the packages removed from the bath. Thus, theoverall bath temperature drop occurring with the addition of a smallamount of water will never be particularly significant so as to causeexcess cooling and upsetting of the cooking process and timing ofheating of food packages in the vessel.

When the cooker/rethermalizer is put into operation, it will be realizedthat a variety of different meat entrees may be inserted at any one timein the multiple of locations in the locator rack, each requiting its ownheating time optimum for that particular type of meat and style ofcooking, as well as each independent packaged sauce being heated for apredetermined optimum time. Packages of vegetables may also be placedwithin certain of these locations and be heated and/or cooked at thesame time. Hence, at any one time the process can become quite complex.To simplify the operation of this potentially complex arrangement, thecontrol panel 100 of the controller 14 (FIGS. 11 and 12) is speciallygraphically designed. One control panel portion 102 has a geometricpattern corresponding to the geometric pattern of the locations of thelocator rack in the cooker/rethermalizer vessel. More specifically,referring to FIGS. 2, 11 and 12, it will be noted that the control panelportion 102 for the specific locations is set forth in a graphic mannerto have a geometric pattern corresponding to and visually simulating thegeometric pattern of the locations in the heater vessel. Therefore, forthe 18 locations depicted for the locator rack, there are 18 spaces onthe geometric pattern 102, with three primary locations along each sidein similar fashion to the rack. These six primary locations each have a"location" timer control button 104 and three "location in use"indicator lights 106 i.e., one light for each of the 18 "locations" inthe bath. Also shown on a second control panel portion 108 is aplurality, here shown to be 12 in number, of "product" button switches110 (in two rows), each having a "product" indicator light 112 and aproduct label space 114. These label spaces are occupied by labels suchas "Beef," "Chicken," or other meat entrees, or labels such as "BernalseSauce" or the like, for particular sauce packages, or vegetable labelssuch as "Carrots," "Cabbage," etc. Each product button is set for thecooking or reheating time of the labelled product.

Operation of the cooker/rethermalizer--timer/controller system startswith one simple rule--within a primary location, load the threelocations front to back in sequence (this was done so that only sixlocation buttons were needed instead of the eighteen that would benecessary if there was one button per location). The operator puts aproduct to be cooked or rethermalized in the "front" location of aprimary location, if a "Beef" package is inserted into the firstlocation, such as in the right front corner, first a "Beef" productbutton switch 110 is pressed on panel 100, causing a product light 112to illuminate, and then the location button switch 104 is pressed thatgraphically represents the three locations of the right front corner.The "beef" time is then transferred to the timer for the right frontcorner and the associated location light 106 for the right front cornerilluminates. Within a primary location the nearest to the front unusedlocation can in similar fashion be loaded with a food, its timer productbutton pushed and then its primary location button pushed ending with alighted location light with an internal associated timer running.

The operator, by looking at the timer/controller can see which locationshave product in them and the digital time display 120 on the controlpanel 102 counts down the time of the nearest to done food product. Thistell nearest to done time lets the operator know when he will next needto act to remove a reheated or cooked food product. When the time forcooking or reheating a food product has elapsed, an audible signal willsound and the location light 106 associated with that food product willblink. The blinking light alerts the operator as to which food productto remove from the bath and which timer location button (within the sameprimary location as the "done" product) to push to cancel the audiblesignal and blinking location light. The timer display 120 will thenillustrate the "nearest to done" time remaining for the next sequentialitem to be removed, and so forth.

Optionally, more than one timer display may be provided. Also, therecould be a separate timer control button 104 for each location.

The example circuitry in FIGS. 10A and 10B was employed on the prototypefor the invention. It may alternatively be substituted by lower cost,printed circuit boards accomplishing the same basic functions, as notedpreviously.

In operation, the vessel is filled with water and heated to a presettemperature. The selected temperature may be anywhere between 140° F.(at which bacteria are killed) and 212° F. (boiling temperature), forexample 145° F. (for holding food, precooking, medium rare beef, and tobe certain to kill bacteria), 160° F. (for cooking chicken or fish),170° F. (to cook lobster), 180° F. (to reheat or rethermalize food),200° F. or 205° F. (to cook vegetables) or 212° F. (to cook pasta). Thetemperature selected is maintained in the bath within about two degrees,by the temperature control sensors and cooperative resistance heaters ofthis apparatus. Individual packages of previously prepared or raw food,e.g., meat entrees and sauces, are inserted sequentially in therespective locations of compartments of the; locator rack, and zones ofthe bath, the insertion of each entry being followed by actuation of aproduct control switch 110 and a location button switch 104 as notedabove, thereby activating the digital timer displayed at 120. When theunit is operated, fluid such as compressed air is continuously injectedinto tubes 50, 62a and 62b. Outlets from tubes 50 cause the fluid,preferably air bubbles, to rise through the bath and over the surfacesof each individual package in each location, to mix the water adjacentall of the packages and cause efficient heat transfer. Simultaneously,fluid such as air is ejected up inverted channel ramps 60a and 60b, andejected diagonally from the upper end outlets thereof in oppositedirections on opposite sides of the vessel, thereby causing the aqueousbath liquid to circulate around the vessel. After the predeterminedheating time for each entry, the package thereof is removed from itslocation, the selected sauce is removed from its location, the packagesare opened and the two items combined on a plate for serving. If avegetable entree is selected, a package of cooked vegetables of selectedtype is removed from its location, opened, and placed on the plate.

Experimental use of the apparatus has shown that it produces excellenthigh quality food products prepared appropriately for the cookingconditions of the particular items, yet without an on-site chef, withfar less space required than conventionally necessary, and withcontrolled production.

If the apparatus is used to cook pasta, a rack not having the locationsbut employing the lower fluid flow tubes and the diagonal ramps may beused. If the fluid injected is air, bubbles pass up through the pasta,e.g., spaghetti, for bath mixing, evenly cooking the pasta, andseparation of the pasta material. The starch that is cooked off thepasta rises to the surface, assisted by the bubbling action, at whichpoint the air or water ejected from the diagonal tube upper end outletsejects the starch from the bath, i.e., over the edge of the vessel intoan appropriate surrounding container (not shown) for easy removal.

It is conceivable that certain details of the development describedabove could be modified from the preferred embodiment set forth anddescribed as exemplary of the invention. Such variations to suit aparticular type of installation or operation are considered to be partof the invention which is intended to be limited only by the scope ofthe appended claims and the reasonable equivalents thereto.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

I claim:
 1. A food preparation cooker/rethermalizer comprising:a foodheating vessel having sides and a bottom for retaining an aqueous bath,and including heat supply for heating the aqueous bath; a food locatorrack in said vessel having a plurality of defined locations forsupporting packaged food items to be heated; said rack having fluidoutlets to said vessel beneath all of said locations to cause fluid toexit into the bath and agitate the bath over and past food items in saidlocations of said food locator rack; and a fluid connector on said rackfor connection to a pressurized source of fluid.
 2. The food preparationcooker/rethermalizer in claim 1 including fluid conducting tubes on saidlocator rack, having said outlets therefrom, and including upwardlydiagonally oriented conduits to conduct pressurized fluid causing bathcirculation.
 3. A food preparation cooker/rethermalizer comprising:afood heating vessel having sides and a bottom for retaining an aqueousbath, and including a heater for heating the aqueous bath; open foodsupport means in said vessel defining a plurality of separate locationsfor supporting food items to be heated, and having upper and lowerportions; said food support means including gas conducting tubes havingoutlets at said lower portion to said vessel, beneath all saidlocations, to cause gas bubbles to exit into the bath and move up alongand past food items on said food support means; connectors from said gasconducting tubes to a pressurized source of gas; said gas conductingtubes including upwardly sloped gas conducting ramps at opposite sidesof said vessel sloped upwardly, in opposite directions.
 4. The foodpreparation cooker/rethermalizer in claim 3 wherein said ramps haveupper end outlets for ejection of gas and water therefrom, to cause bathcirculation in said vessel.
 5. A food preparation cooker/rethermalizercomprising:a food heating vessel having sides and a bottom for retainingan aqueous bath, and including a heater for heating the aqueous bath; afood support in said vessel; fluid conducting tubes in said vessel at anangle along said sides comprising an outlet oriented at an angle alongsaid sides to cause bath circulation by fluid ejected from said outlet;said fluid conducting tubes comprising a pair of fluid outlets orientedin opposite directions along said opposite sides to cause bathcirculation by fluid ejected from said outlets.
 6. A food preparationheating vessel for an aqueous bath, comprising:a food heating vesselhaving sides and a bottom for retaining an aqueous bath, and having aheat source; an open food support means in said vessel for supportingfood items to be heated; said food support means including fluidconducting tubes and having outlets from said tubes to said vessel forcausing fluid to leave said tubes and flow between the food items; andat least one upwardly, diagonally ramped conduit adjacent one of saidvessel walls, having an upper end with an outlet thereat, to cause fluidflow therefrom for circulation of the aqueous bath in said vessel. 7.The food preparation heating vessel in claim 6 characterized by saidtubes having means for connecting to a pressurized gas fluid source,having central bubble tubes adjacent said vessel bottom, with bubbleoutlets therealong for flow of gas bubbles up along packaged food itemsin said food support means, and said at least one ramp conduitcomprising a pair of such ramp conduits at opposite sides of said vesseldiagonally oriented in opposite directions for effecting bathcirculation in said vessel.
 8. The food preparation cooker/rethermalizerin claim 1 characterized in that said heat supply means comprises aheater element embedded in rubber-type material bonded to said vessel onthe outside thereof.
 9. The food preparation cooker/rethermalizer inclaims 8 characterized in that said heater element is an electricresistance heater coil embedded between layers of rubber-type materialbonded to said vessel.
 10. The food preparation cooker/rethermalizer inclaim 9 wherein said rubber-type material is silicone polymer.
 11. Thefood preparation cooker/rethermalizer in claim 1 including a graphiccontrol panel;said food support means having said plurality of locationsfor retaining food arranged in a geometric location pattern; saidgraphic control panel having controls and indicators for each of saidlocations, arranged in a geometric control pattern visually simulatingsaid geometric location pattern.
 12. The food preparationcooker/rethermalizer in claim 1 including a housing, said vessel beingin a vessel chamber in one portion of said housing;said housing alsodefining an electronics control chamber; a pair of spaceLl walls betweensaid vessel chamber and said electronics control chamber forming avertically elongated space therebetween, said pair of walls including avessel chamber wall and an electronics control chamber wall; air inletopening means at the bottom of said space for admitting air, and airoutlet opening means at the top of said space for exhausting air, sothat said space acts like a chimney with thermal convection driven,ambient air flow therethrough for thermally isolating said electronicscontrol chamber from said vessel chamber.
 13. The thermalizing apparatusin claim 12 including a fluid inlet oriented for causing fluid generatedcirculation.
 14. A pasta cooker comprising:a pasta heating water vesselhaving sides, bottom, and an at least partially open top with a topoutlet for starch cooked off the pasta in said vessel; a pasta supportin said vessel, comprising fluid conducting tubes including at least onediagonally upwardly extending tube oriented toward said top outlet andhaving a fluid outlet adjacent the upper end thereof, so that ejectionof fluid from said outlet causes floating starch cooked off the pasta tobe ejected through said top outlet; and said tubes having means forconnection to a fluid source.
 15. The pasta cooker in claim 14 whereinsaid pasta support has fluid conducting bottom tubes adjacent the bottomof said basket, and orifices in said bottom tubes for ejecting fluid uppast the pasta in said cooker to facilitate heat exchange at the pastaand elevate starch to the top of the bath.
 16. The pasta cooker in claim14wherein said pasta support includes a pair of said diagonally upwardlyextending tubes adjacent opposite sides of said vessel and having upperend outlets oriented in opposite directions to cause water circulationin said vessel, as well as starch ejection.
 17. A pasta cookercomprising:a pasta heating vessel having side and bottom walls forretaining an aqueous bath; a pasta support in said vessel; a pressurizedgas conducting and emitting conduit in said vessel for causing gasbubbles to pass through pasta in said pasta support; and a fluidconducting, bath circulating conduit in said vessel having an outletoriented to cause bath circulation.
 18. The food preparationcooker/rethermalizer in claim 1 whereinsaid sides and bottom haveinterior surfaces and exterior surfaces; vessel heater means on saidexterior surfaces for heating the aqueous bath and food in said vessel;said vessel heater means including polymer bonded to said exteriorsurfaces and electrical resistance heater elements embedded in saidpolymer; and said heater elements having connection means for connectionto an electrical power source.
 19. The food preparation heating vesselin claim 18 wherein said resistance heater elements comprise helicalcoils, and said polymer is a silicone polymer.
 20. The food preparationheating vessel in claim 19 wherein said polymer comprises layers ofsilicone rubber, with one layer adjacent to and bonded to said exteriorsurfaces, and said elements being embedded between said layers.
 21. Thefood preparation cooker/rethermalizer in claim 1, further comprisingwater supply means for supplying additional water to said vessel toreplace water lost by evaporation and removal with food items;sensingelements at spaced, different vertical locations of said vessel, anupper one at the level desired for the bath, and a lower one below thatlevel for detecting the differential sensed by said sensing elements;and said sensing elements being operably associated with said watersupply means for periodically actuating said water supply means to addsupplemental water to said vessel when a predetermined differential isdetected.
 22. The food preparation cooker/rethermalizer in claim 21wherein said sensing elements are temperature sensing elements.
 23. Thefood preparation cooker/rethermalizer in claim 21 wherein said heater isattached to said vessel, and said upper sensor is above said heater. 24.The food preparation cooker/rethermalizer in claim 3, furthercomprising:said vessel defining zones of the bath; said heatercomprising a plurality of heaters for said vessel; said vessel having aplurality of defined locations in a geometric location pattern forsupporting items to be thermalized in the bath; said heaters beinglocated at respective ones of said zones of said geometric locationpattern; a graphic control panel having controls and indicators for eachof said zones, arranged in a geometric control pattern visuallysimulating said geometric location pattern whereby a thermal load in onezone does not materially drive the temperature in another zone up ordown.
 25. The thermalizing apparatus in claim 24 including a pressurizedfluid inlet for bath agitation.
 26. The thermalizing apparatus in claim24 including a fluid inlet oriented for causing fluid generatedcirculation.
 27. The food preparation cooker/retherrnalizer in claim 6,further comprising:a housing having walls defining a heating chamber, acontrol chamber and an isolation space therebetween; said food heatingvessel being in said heating chamber, and said heat source comprising aheater for said vessel; said isolation space having an ambient air inletadjacent the bottom thereof and an air outlet adjacent the top thereofto thereby create a chimney-like convection flow of ambient air uptherethrough, to thermally isolate said chambers.
 28. The foodpreparation heating apparatus in claim 7, further comprising:a housingdefining a heating chamber and a separate control chamber; said foodheating vessel being in said heating chamber, and including said heatsource; electronic controls in said electronic control chamber; twowalls between said chambers, spaced from each other and defining avertically elongated space therebetween, one of said two walls being awall of said heating chamber, and the other wall being a wall of saidcontrol chamber; air inlet opening means at the bottom of said space forinlet air flow; air outlet opening means at the top of said space foroutlet air flow into said heating chamber, whereby heat from saidheating chamber creates thermally-generated, upward air flow throughsaid space to isolate and cool said control chamber wall.
 29. The foodpreparation cooker/rethermalizer in claim 1, further comprising:openfood support means in said vessel forming a plurality of definedlocations for retaining individual food packages separated from eachother; said locations being arranged in a geometric pattern; a graphiccontrol panel for said cooker/rethermalizer including controls andindicators for the respective locations; and said graphic control panelbeing arranged in a geometric control pattern visually simulating saidlocation pattern.
 30. The food preparation cooker/rethermalizer in claim29 wherein said control panel has boundary lines forming a plurality ofoutlines simulating all of said locations, each location-simulatingoutline including a timer control and an indicator.
 31. The foodpreparation cooker/rethermalizer in claim 30 wherein said control panelalso includes a separate segment with zones, each zone includingactuator controls operably associated with said location-simulatingoutline controls for selective actuation of controls for food in each ofsaid locations.
 32. The apparatus in claim 5, further comprising:saidheater being on said vessel sides; temperature sensors on said sides,including at least one upper sensor on one of said sides and one lowersensor adjacent said bottom, said upper and lower sensors beingvertically spaced from each other and operably associated with saidheater in a fashion to activate said heater when the average of thetemperatures sensed by the upper and lower sensors drops to apredetermined value.
 33. The apparatus in claim 32 wherein said heateris a heater jacket on said vessel sides.